Computing device display screen or portion thereof with a graphical user interface



The FIGURE is a front view of a computing device display screen or portion thereof with a graphical user interface in accordance with the claimed design.

The dot-dash broken line showing of the computing device display screen or portion thereof is for the purpose of illustrating portions of the article and forms no part of the claimed design. The remaining broken lines in the drawing showing portions of the graphical user interface is for the purpose of illustrating portions of the article, and form no part of the claimed design. 

CLAIM The ornamental design for a computing device display screen or portion thereof with a graphical user interface, as shown and described. 